The purpose of this study is to identify retinal specializations peculiar to the rod dominated retina of Aotes in terms of neuronal connectivity and ganglion cell receptive field properties. Contacts of retinal cells stained by the golgi procedure will be evaluated by light and electron microscopy. Serially sectioned cell processes will be reconstructed by computer. The function of retinal ganglion cells will be evaluated with microelectrode recordings from the retina and optic nerve. Thus evidence of the existence, function and possible interaction of rod and cone pathways within the retina of Aotes will be sought.